Combination holder, guard, and hood for portable grinding wheels



, 1934- R. B. RICHARDSON ,0

COMBINATION HOLDER, GUARD, AND HOODFOR PORTABLE GRINDING WHEELS Filed Jan. 27. 1932 INVENTOR a Hubert D. fizflhardsnn [$140 BY //l J WW 1' I 1 ATTORNEYS Patented Oct. 16, 1934 usurp STATE qmmuusrmmm ooMeiNArioN HOLDER, GUARD, AND noon ron PORTABLE GarNnrNG WHEELS Robert B. Rich-artisan, Detroit, Mich.

Application January 27, 1932, Serial No. 589,093

Claims. (01. 51-470) The present invention pertains to a novel combination holder, guard and suction hood for portable'grinding wheels, particularly Wheels of the type used for polishing terrazzo and similar floors.

5 The principal object of the invention is to provide means, in conjunction with the usual support and guard for the grinding wheel, for effectively carrying away the dust.

This dust is very unhealthy and often fatal when inhaled over a considerable period of time, and some States have already passed laws requiring the use of adequate means for carrying the dust away from the grinding wheel. Where suction has been employed for this purpose in other grinding arts, a large intake at the wheel and a comparatively low suction has been used. In the present case, however, due to the portability of the'device, a large dust intake is not feasible; and accordingly, the present invention provides a compact and readily portable suction device having a comparatively small intake and operating under high suction.

A further object of the invention is to incorporate the suction means in the same structure that constitutes the usual dust guard and bearing for the grinding wheel. The suction hood is so designed, in the interest of compactness and in keeping with the main object of the invention, that all parts of it lie close to the wheel and it aohas the appearance of a dust guard. Moreover,

one of the walls of the suction device is prolonged in the direction of rotationof the wheel to provide a dust guard which, in conjunction with the suction hood, covers approximately half the cir- "cumference of the wheel.

The invention is fully disclosed by way of example in the following description and in the accompanying drawing, in which- Figure 1 is an end view of the device;

Fig. 2 is a side elevation;

Fig. 3 is a cross section thereof in the upright position and Fig. 4 is a longitudinal section.

Reference to these views will now be made by use of like characters which are employed to designate corresponding parts throughout.

In Figure 1 is illustrated a holder comprising a bearing 1 in which is journaled one end of a shaft 2 which carries a cylindrical grinding wheel 3 at an end of the bearing. The other end of the bearing is open at 4 for connection of a flexible shaft 5 to the shaft 2 in any suitable manner. Over the wheel 3 and preferably integral with the bearing 1 is formed a pair of spaced walls 6 and 7 which constitute a suction hood and form a slot at the lower end. The inner wall 6 is preferably curved, concentric with the wheel 3 and spaced only slightly from the circumference of-the wheel. The wall 7 may extend beyond the free edge of the wall 6, as indicated by the numeral 8 to form a i mouth 9 between the free edges of the walls, which, in effect, tends to face the wheel 3. The slot extends lengthwise of the wheel, as shown more clearly in Figures 2 and 4 and has an area which is comparable to the area of conduit. In f in order to obtain maximum convenience and use a suction line of minimum size, the conduit 11, 12 is of substantially uniform cross sectional area throughout and does not at any point exceed the area of the slot by more than twenty-five percent The wheel 3 turns upwardly towards the open end of slot so that the dust produced thereby is drawn into the slot and space 10. The suction in the pipe 13 is suflicient to carry off the dust effectively and is comparatively high with relation to the area of the slot.

In order to cover the upper half of the grinding wheel to protect the operator from pieces that inay'break off the wheel, the inner wall 6 is prolonged'beyond the connection of the space 10 with the conduit 11 to form a guard 14. It will be evident that the hood consisting of the walls 6 and 7 covers the wheel and also functions as a guard in the same manner as the member 14.

The ends of the space 10 are preferably closed by end Walls 15 and 16 so that the intake under suction is confined to the slot. of the wheel projects beyond the wall 15 for operating reasons, the suction in the slot is high enough to be effective over the entire length of the wheel where it engages the floor or other part being polished.

An upright handle 17 is formed over the conduit 11, and the operator in using the tool grasps this handle with one hand and the suction conduit 12 with the other hand. It will also be seen that the various parts constituting the bearing, suctioned symmetrical to a vertical plane extending t]? Although one end 95 lengthwise of shaft 2; hence, in this position, substantially all of the guard structure lies above a horizontal plane extending lengthwise of such shaft, the result being that the entire lower face of the wheel 3 is an exposed face. Obviously, therefore, the structure will permit of rather wide range of swing of the guard structure without bringing any portion of the latter into contact with the surface being ground. And since the guard structure itself is practically symmetrical to such vertical plane, it is obvious that during swinging movements, the weight factor is more or less distributed, with the preponderance developing gradually when present.

The advantage or this arrangement lies in the fact that the assembly can be used to meet varied conditions in the floor surface or even reach to curved surfaces which project upwardly above the normal plane or" the floor, it being necessary only to shift the guard on its axis, the angular distance of expos re or" the wheel remaining constant; hence, it is necessary only to swing the handle to the proper degree for eflicient service. The handle being located above and approximately midway in the axial length of the wheel, will efficiently guide the structure; and as the suction ofi-take 12 is integral with and necessarily partakes of the handle movements, the swinging of the handle can be provided without liability of line entanglement.

While the handle swinging movements thus enable the structure to meet varied conditions or" service, such movements also serve to meet the dust conditions, since, by swinging the handle, the mouth 9 can be swung as close as desired to the point where the dust has its exit from the con tact zone of the wheel and surface being ground, whether the surface is fiat or otherwise. In other words, the position of the handle and the direcion of its oscillation is such that the structure can be pushed or drawn and at the same time be subject to the desired downward pressure, a condition which permits approximately half the wheel surface to be permanently exposed to meet the varied grinding conditions and at the same tim pe mit adjustment of the dust nozzle to a position where it will be most eiiective for the purpose.

Although a specific embodiment of the invention has been illustrated and described, it will be understood that various alterations in the details of construction may be made without departing from the scope or" the invention, as indicated by the appended claims.

What I claim is:-

1. In portable grinding devices, and in combination, a grinding wheel of extended axial length and its driving means with the wheel at an end of the shaft of such driving means, a guard therefor mounted to swing on the shaft axis and having a face substantially concentric with and in proximity to the wheel face, said guard having an angular length approximately equal to half the peripheral length of the wheel, a handle carried by the guard substantially mid-way of the length of the wheel, whereby the guard may be swung about the wheel by the handle with the latter active in any of the swing positions to advance the device and apply pressure thereto, said guard including a suction nozzle and oil-take adapted to be operatively connected to a suction source, said nozzle having a mouth at one of the side edges of the guard and opening toward the wheel surface, whereby the suction mouth may be shifted to a position adjacent the point of exit of dust particles from the grinding zone at will and under service conditions in which such point of exit position may vary within an extended arouate range of the exposed periphery of the wheel.

2. A device as in claim 1 characterized in that the inner and outer lips of the mouth are located on angulariy-spaced radii of the wheel with the outer lip spaced the greater distancefrom the axis of the off-take, whereby the mouth tends to face the peripheral face of the wheel.

3. A device as in claim 1 characterized in that the cross-secticnal area of the suction off-take is ubstantially twenty-five per centum. greater than that of the mouth of the nozzle.

4. A device as in claim 1 characterized in that the axis of the off-take is located on the radial plane of the wheel axis and laterally of the handle in the direction of the length of the wheel, the guard having a conduit connecting the off-take with the mouth of the nozzle.

5. A device as in claim 1, characterized in that.

the take-elf and guard structures are integral, with the take-off positioned radially outward from the wheel axis and extending parallel therewith and with the handle extending radially of said wheel axis outwardly from said guard structure in the same radial direction as said take-off, said guard having a conduit connecting the integral end of the take-01f with the mouth of said nozzle.

ROBERT B. RICHARDSON;

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